Lipoquinones of some bacteria and mycoplasmas, with considerations on their functional significance

Abstract

In a comparative study the lipoquinones of some chemoorganotrophic, facultatively aerobic bacteria, and representative Acholeplasma, Mycoplasma, Spiroplasma, and Thermoplasma strains were investigated. The quinones were partly purified by preparative thin layer chromatography of lipid extracts, and characterized by their difference spectra (reduced minus oxidized) and Rf values. Respiring bacteria expectedly contained benzoquinones and/or naphthoquinones in micromolar concentrations whereas some aerotolerant, cytochrome-less, gram-positive bacteria were found to contain menaquinones in nanomolar concentrations, or even no quinones; only Streptococcus faecalis, an organism supposed to use a rudimentary, flavin-terminated respiratory chain system produced desmethyl menaquinone in amounts ranging between "high" and "low" quinone contents. Among the mycoplasmas investigated, only Thermoplasma acidophilum was found to be capable of synthesizing quinones (MK-7) in the micromolar order of magnitude indicating a respiratory electron transport system. The presence of energetically useful respiratory chain systems in Acholeplasma, Mycoplasma, and Spiroplasma is questioned since these organisms contain quinones (MK-4) in nanomolar concentrations, or no quinones, depending on the presence of exogeneous MK-6 in the growth medium. The possible metabolite role of menaquinones present in "low" amounts, as well as the role of NADH oxidase systems more or less tightly bound to the cytoplasmic membrane with the mycoplasmas deserves further investigation.

Utilization of Microbial Biofilms as Monitors of Bioremediation

“…Respiratory quinones are found in concentrations at least 200 times less than the PLFA or about 0.5 lmole/g dry weight [12], but can be quantified at high specificity and sensitivity with LC/MS/MS [17,18]. Respiration, including respiration of U, is mediated by quinones.…”

Lipoquinones of some Spore-forming Rods, Lactic-acid Bacteria and Actinomycetes

“…Extraction and determination of quinones andprotein. The quinones were extracted as previously described (Hollander et al, 1977) and their isoprenologues were determined by reversed-phase thin-layer chromatography on kieselgel 60 (Merck, Darmstadt, F.R.G.) impregnated with paraffin according to Dunphy et al (1971).…”

The Cytochromes of Thermoplasma acidophilum

“…The difference spectra of the CO-treated cells of both strains grown aerobically showed the characteristics of cytochrome o at 558 nm, and a shift of 7 nm to longer wavelength in the absorption of cytochrome d(a,); these were not detected with cells grown in oxygen-limited conditions. The presence of cytochromes, cytochrome oxidases and menaquinones (Langworthy et al, 1972;Belly et al, 1973;Hollander et al, 1977) in amounts similar to those in respiring, cell wall-synthesizing bacteria indicated the presence of intact, oxidative, terminal electron transport systems in the Thermoplasma strains investigated. These properties distinguished the Thermoplasma strains from other members of the class Mollicutes in which quinones and cytochromes in comparable amounts have not been detected (Rodwell & Rodwell, 1954;Gale et al, 1964;Smith et al, 1963;Hollander et al, 1977).…”

“…arthritidis strain 07 grown in PPLO-broth (Difco) supplemented with 20 yo (v/v) horse serum and 1 yo (w/v) yeast extract (Hollander et al, 1977).…”

“…This is probably the reason for the equivocal reports so far presented on the cytochromes of the mycoplasmas (Van Demark, 1969;Van Demark & Smith, 1964). Members of the Acholeplasma, Mycoplasma and Spiroplasma group contain very small amounts of menaquinones when grown in peptone media supplemented with horse serum, but these probably have no respiratory function (Hollander et a/., 1977). However, Thermoplasma acidophilum synthesizes menaquinone-7 in amounts similar to those of respiring bacteria (Langworthy et al, 1972;Hollander et al, 1977) and also c-type cytochromes (Belly et a/., 1973).…”